Trans person here. It depends on which hormone therapy you’re taking.

Testosterone has a tendency to override feminizing hormones, so people who are on FtM HRT often only need to take testosterone and submit annual blood panels. But since testosterone is literally toxic in high quantities, and can cause heart palpitations, it needs to be administered carefully. Transmasc folks either go into a clinic to have it administered, or in some places they’re trained on how to safely self-administer.

If you’re transfemme, you have to take a cocktail of medications, since feminizing hormones have a slightly more complex response than just T. MtF people need antiandrogens, progestogens, and estrogen for their therapy. Estrogen is the real heavy lifter for most of this, but progesterone is important for things like growing tits.

Of course, not everyone can go on HRT, which is why transmedicalism (the idea that you’re only valid as a trans person if you’re pursuing medical transition like HRT and surgery) is frowned upon in most corners of the queer community. Some people have serious endocrine or cardiovascular illnesses that make HRT dangerous. Other people, especially in countries where being queer carries the death penalty, already are at risk for voicing their thoughts and feelings. They’re exactly as trans as I am, whether or no they’re on HRT.